No it wasn't, you were always tied to being where your TV was. Just because you could play on the tablet controller right by your TV does not mean it offered portable gameplay. I could not play mine from my truck during my break at work like I can the Switch or a dedicated handheld device, therefore it is not a portable by any means.
Yes it was.
The fact you had a tablet as a controller and can do off-screen gaming was a testament to that, the distance from your "base station/console" was just a limitation.
Fair enough. 3rd gen, but first gen as a mainstream device. Neither of those made the impact that the Switch is now.
It is one or the other. Because some of those other devices were "mainstream". - Or do you have another goal post to shift towards? I.E. Sales/Popularity?
If we are going to group them in with android powered devices, then we may as well group the PS4 and X1 into the same category as different PC builds. That would certainly put them anywhere else than the "gen 8" most people try to put them in.
Not grouping them with anything, just the general concepts have existed much longer than the Switch has existed.
But sure, if you want to group that Playstation 4 and Xbox One with the PC, go right ahead, got nothing against that.